Premixed turbulent flame calculation

The importance of turbulent premixed flames in a variety of applications has led to a substantial amount of effort towards improving the understanding of these flames. Although these efforts have increased the understanding, many questions still remain. The use of direct numerical simulation (DNS) in solving these questions is examined

Assessment of STEM e-Learning in an Immersive Virtual Reality (VR) Environment

This paper shows the early research findings of utilizing a virtual reality environment as an educational tool for the operation of a computerized numerical control (CNC) milling machine. Based off of a previous work, the Advanced Virtual Machining Lab (AVML), this project features a virtual environment in which a virtual CNC machine is fully operable, designed to allow STEM students and training professionals to learn the use of the CNC machine without the need to be in a physical lab. Users operate in the virtual environment using an immersive virtual reality headset (i.e. Oculus Rift) and standard input devices (i.e. mouse and keyboard), both of which combined make for easy movement and realistic visuals. On-screen tutorials allow users to learn about what they need to do to operate the machine without the need for outside instruction. While designing and perfecting this environment has been the primary focus of this project thus far, the research goal is to test the ease of use and the pedagogical effectiveness of the immersive technology as it relates to education in STEM fields. Initial usability studies for this environment featured students from the graduate level CAD/CAM-Theory and Advanced Applications (ME 54600) course at IUPUI. Results from the study were tabulated with a survey using a four-point Likert scale and several open-ended questions. Findings from the survey indicate that the majority of users found the environment realistic and easy to navigate, in addition to finding the immersive technology to be beneficial. Many also indicated that they felt comfortable navigating the environment without the need for additional assistance from the survey proctors. Full details on the first usability study, including data and discussion, can be found in this paper. The general consensus from the study was that, while some features needed refinement, the immersive environment helped them learn about the operation of a CNC machine. Additional usability studies will need to be undergone to refine said features before beginning the final study, in which students learning from the immersive virtual environment will be tested against students learning from traditional methods. Details on this last study will be discussed in the final paper, which will also discuss the methods used for preparing the environment, full results and detailed discussion on each of the usability studies, and conclusions on the usability and educational effectiveness of the immersive virtual reality technology in STEM education

Application of the group-theoretical method to physical problems

The concept of the theory of continuous groups of transformations has attracted the attention of applied mathematicians and engineers to solve many physical problems in the engineering sciences. Three applications are presented in this paper. The first one is the problem of time-dependent vertical temperature distribution in a stagnant lake. Two cases have been considered for the forms of the water parameters, namely water density and thermal conductivity. The second application is the unsteady free-convective boundary-layer flow on a non-isothermal vertical flat plate. The third application is the study of the dispersion of gaseous pollutants in the presence of a temperature inversion. The results are found in closed form and the effect of parameters are discussed

Small-Cell Lung Cancer: 8 Years Experience of a Single Multidisciplinary Team

Aims. We have audited the changes in treatment practice for small-cell lung cancer (SCLC) presented to a single multidisciplinary team (MDT) at Doncaster and Bassetlaw Hospitals between January 1998 and December 2005. Materials and Methods. The MDT database was used to identify all patients with SCLC. Anonymised demographic, treatment, and outcome details were extracted from the database supplemented by patient records. Results. 235 patients were identified. 112 (48%) had limited disease at presentation. Chemotherapy was the initial treatment for 195 patients, 77% of whom had a documented radiological response with a complete response in 24%. Chemotherapy regimes evolved during the study period with the increasing use of platinum-based chemotherapy. Anthracycline-based chemotherapy was most used before 2004 and was given to 57% of all patients. 42% received consolidation thoracic radiotherapy and 24% prophylactic cranial irradiation. The median and 2-year survival were 8 months and 18%, respectively, for patients with limited disease and 5 months and 5%, respectively, for extensive disease. Conclusion. We have documented changes in treatment practice and service delivery of SCLC over the 8 years during which the MDT has been operating. However, there has not achieve any significant improvement in outcome for the population of patients with SCLC

From white elephant to Nobel Prize: Dennis Gabor’s wavefront reconstruction

Dennis Gabor devised a new concept for optical imaging in 1947 that went by a variety of names over the following decade: holoscopy, wavefront reconstruction, interference microscopy, diffraction microscopy and Gaboroscopy. A well-connected and creative research engineer, Gabor worked actively to publicize and exploit his concept, but the scheme failed to capture the interest of many researchers. Gabor’s theory was repeatedly deemed unintuitive and baffling; the technique was appraised by his contemporaries to be of dubious practicality and, at best, constrained to a narrow branch of science. By the late 1950s, Gabor’s subject had been assessed by its handful of practitioners to be a white elephant. Nevertheless, the concept was later rehabilitated by the research of Emmett Leith and Juris Upatnieks at the University of Michigan, and Yury Denisyuk at the Vavilov Institute in Leningrad. What had been judged a failure was recast as a success: evaluations of Gabor’s work were transformed during the 1960s, when it was represented as the foundation on which to construct the new and distinctly different subject of holography, a re-evaluation that gained the Nobel Prize for Physics for Gabor alone in 1971. This paper focuses on the difficulties experienced in constructing a meaningful subject, a practical application and a viable technical community from Gabor’s ideas during the decade 1947-1957

On backward stochastic differential equations and strict local martingales

We study a backward stochastic differential equation whose terminal condition is an integrable function of a local martingale and generator has bounded growth in $z$. When the local martingale is a strict local martingale, the BSDE admits at least two different solutions. Other than a solution whose first component is of class D, there exists another solution whose first component is not of class D and strictly dominates the class D solution. Both solutions are $\mathbb{L}^p$ integrable for any $0<p<1$. These two different BSDE solutions generate different viscosity solutions to the associated quasi-linear partial differential equation. On the contrary, when a Lyapunov function exists, the local martingale is a martingale and the quasi-linear equation admits a unique viscosity solution of at most linear growth.Comment: Keywords: Backward stochastic differential equation, strict local martingale, viscosity solution, comparison theore

Resolvent of Large Random Graphs

We analyze the convergence of the spectrum of large random graphs to the spectrum of a limit infinite graph. We apply these results to graphs converging locally to trees and derive a new formula for the Stieljes transform of the spectral measure of such graphs. We illustrate our results on the uniform regular graphs, Erdos-Renyi graphs and preferential attachment graphs. We sketch examples of application for weighted graphs, bipartite graphs and the uniform spanning tree of n vertices.Comment: 21 pages, 1 figur

Solitons of the Resonant Nonlinear Schrodinger Equation with Nontrivial Boundary Conditions and Hirota Bilinear Method

Physically relevant soliton solutions of the resonant nonlinear Schrodinger (RNLS) equation with nontrivial boundary conditions, recently proposed for description of uniaxial waves in a cold collisionless plasma, are considered in the Hirota bilinear approach. By the Madelung representation, the model is transformed to the reaction-diffusion analog of the NLS equation for which the bilinear representation, soliton solutions and their mutual interactions are studied.Comment: 15 pages, 1 figure, talk presented in Workshop `Nonlinear Physics IV: Theory and Experiment`, 22-30 June 2006, Gallipoli, Ital

Municipalities Collaborating in Public Health: The Danish Smoking Prevention and Cessation Partnership

This study explored the Smoking Prevention and Cessation Partnership (SPCP) which builds upon a collaboration between two Danish municipalities targeted at the prevention of tobacco smoking. The aim of the study was to describe the processes of SPCP, to examine the difficulties this collaboration faced, and to assess how these experiences could be used to improve future partnership collaboration. We employed qualitative methodology comprising 12 semi-structured one-to-one interviews with SPCP’s stakeholders and an analysis of the partnership documents and reports. The findings suggested that the main potentials of the partnership were the personal relations between the members and stakeholders with the possibilities of the creation of new connections with other actors. Barriers to successful partnership building were the implementation of the new Local Government Reform as a competing task, and that the two municipalities were heterogenic in respect to organizational issues and working methods. Other impediments included the lack of continuity in leadership, the lack of clarity regarding the form of collaboration and roles, as well as different expectations of the stakeholders. We conclude that four factors remain critical for partnerships. The first is the clarity of the collaborative effort. Second, partnerships need to take into account the structural circumstances and culture/value systems of all stakeholders. Third is the impact of contextual factors on the development of the partnership; and the fourth factor is the bearing of personal/individual factors on the partnership e.g., personal engagement in the project. Early attention to these four factors could contribute to more effective partnership working

Trail Making Test performance contributes to subjective judgment of visual efficiency in older adults

Introduction: The determinant factors that influence self-reported quality of vision have yet to be fully elucidated. This study evaluated a range of contextual information, established psychophysical tests, and in particular, a series of cognitive tests as potentially novel determinant factors.   Materials & Methods: Community dwelling adults (aged 50+) recruited to Wave 1 of The Irish Longitudinal Study on Ageing, excluding those registered blind, participated in this study (N = 5,021). Self-reports of vision were analysed in relation to visual acuity and contrast sensitivity, ocular pathology, visual (Choice Response Time task; Trail Making Test) and global cognition. Contextual factors such as having visited an optometrist and wearing glasses were also considered. Ordinal logistic regression was used to determine univariate and multivariate associations.   Results and Discussion: Poor Trail Making Test performance (Odds ratio, OR = 1.36), visual acuity (OR = 1.72) and ocular pathology (OR = 2.25) were determinant factors for poor versus excellent vision in self-reports. Education, wealth, age, depressive symptoms and general cognitive fitness also contributed to determining self-reported vision.   Conclusions: Trail Making Test contribution to self-reports may capture higher level visual processing and should be considered when using self-reports to assess vision and its role in cognitive and functional health